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Few divers know about Mexico's sardine run yet it rivals its equivalent in South Africa and is an awe-inspiring display. READ MORE…
8 Great Liveaboard Deals for 2024 - Save 40%
We bring you news of some fantastic dive boat deals in 2024, specially selected for us by Divebooker.com, the liveaboard specialists. Including 5, 7, 9 and 10 night trips in the Pacific Ocean, Indian Ocean, Caribbean and Red Sea.
Theia, Maldives Central Route, 2 06 - 13 April 2024 (7 nights), SAVE UP TO 30%, Price from USD 2,495 1,996 per trip per person
Clever Cuttlefish is Creature of the Month
Diver and cuttlefish in Malta. Slepenkov Igo/DepositPhotos
Master of Camouflage even though Colour-Blind
The cuttlefish is a fascinating creature. This intelligent mollusc has almost incredible powers of mimicry. It can control the colour, patterning and texture of its skin to perfectly match its surroundings. And not just from above, the camouflage works from whichever angle it is observed. From birth, cuttlefish can display at least 13 type of body pattern, made up from over 30 different components. And all this whilst being colour-blind.
Cuttlefish camouflage. Tim Nicholson
Cuttlefish Courtship
In addition to avoiding predators, pattern control is also used in courtship by male cuttlefish. This impresses females and warns off competitors. After mating the male will often defend the female while she lays clumps of eggs. These hatch in two to three months to reveal miniature cuttlefish. Females only breed once and die soon after laying.
Mating cuttlefish in Daymaniyat, Oman. A. Nikolaev/DepositPhotos
Jet Propulsion
With its flattened body skirted each side with fins, the cuttlefish moves with a pretty rippling motion. Like the closely related octopus, it can also escape by powerful jet propulsion whilst simultaneously ejecting a cloud of black ink to distract its foe. This ink is called sepia and was once used by artists.
10 Arms and 3 Hearts
The cuttlefish's mouth is surrounded by eight arms. It also has two long extendable tentacles and is thus classified as a decapod (10 feet). Carnivorous, cuttlefish catch fast-moving prey like crustaceans and fish with their long tentacles. Two of their three hearts send blood to the gills, the other pumps blood around the body.
In this photo the cuttlefish is raising its tentacles in an aggressive posture. Captain Victor Organ
Bouyancy control in their bones
The Cuttlefish bone is filled with small chambers. They fill or release air from these chambers to control their buoyancy.
Of course, being an invertebrate the cuttlefish bone is not really a bone, more of an internal shell.
Cuttlefish at Agincourt Reef, Australia. Tim Nicholson
Clever Cuttlefish
A recent study showed that like some vertebrates, cuttlefish can exert self-control for over two minutes at a time.
Cuttlefish will wait for a better but delayed reward of their favourite food. In the tests, all cuttlefish liked live grass shrimps best, pieces of raw king prawn came next and Asian shore crab was the least preferred.
The cleverest cuttlefish, that learnt the most quickly, could wait for longer. Chimpanzees, dogs and grey parrots have been shown to employ strategies such as looking away, closing their eyes or distracting themselves with other objects while waiting for a better reward. Interestingly, cuttlefish were observed turning their body away from the immediately available prey item as well, as if to distract themselves when they needed to delay immediate gratification.
Underwater Photographer of the Year announced The winner was Alex Dawson from Sweden, for his arresting image: "Whale Bones". A breath-hold diver descends below the Greenland ice sheet to bear witness to slaughtered whales.
Colossal Cruise Ships - even more reasons to worry The "Icon of the Seas" cruise ship holds over 10,000 people. Cruise ships dump millions of litres of treated sewage and wastewater on each voyage and engine noise interferes with the ability of killer whales and other cetaceans to echolocate.
Dive sites reopen in Bonaire Some sites in the north and Klein Bonaire were temporarily closed for a period. However, all dive sites are now open, with the exception of Washington Slagbaai Park, which remains closed for diving.
Cold-water coral traps itself on mountains in the deep sea Corals searching for food in the cold and dark waters of the deep sea are building higher and higher mountains. But in doing so, they may find themselves trapped when the climate changes.
Global shark deaths increasing despite finning bans A new study finds that shark mortality increased by 4% in coastal fisheries between 2012 and 2019, despite legislation to ban shark finning increasing tenfold over this period.
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Photo credits: John A. Anderson, A. Nikolaev, Andrea Izzotti/DepositPhotos, Captain Victor Organ, Tim Nicholson, Jill Studholme
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